/*
 * Copyright (c) 2006, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package com.sun.corba.se.spi.orbutil.threadpool;

import java.io.Closeable ;

/** This interface defines a thread pool execution service.  The ORB uses this
 * interface, which preceeds the JDK 5 ExecutorService.  Note that the close
 * method must be called in order to reclaim thread resources.
 */
public interface ThreadPool extends Closeable
{ 

    /** 
    * This method will return any instance of the WorkQueue. If the ThreadPool 
    * instance only services one WorkQueue then that WorkQueue instance will 
    * be returned. If there are more than one WorkQueues serviced by this 
    * ThreadPool, then this method would return a WorkQueue based on the 
    * implementation of the class that implements this interface. For PE 8.0 we 
    * would return a WorkQueue in a roundrobin fashion everytime this method 
    * is called. In the future we could allow pluggability of  Policy objects for this. 
    */ 
    public WorkQueue getAnyWorkQueue(); 

    /** 
    * This method will return an instance of the of the WorkQueue given a queueId. 
    * This will be useful in situations where there are more than one WorkQueues 
    * managed by the ThreadPool and the user of the ThreadPool wants to always use 
    * the same WorkQueue for doing the Work. 
    * If the number of WorkQueues in the ThreadPool are 10, then queueIds will go 
    * from 0-9
    * 
    * @throws NoSuchWorkQueueException thrown when queueId passed is invalid
    */ 
    public WorkQueue getWorkQueue(int queueId) throws NoSuchWorkQueueException;

    /** 
    * This method will return the number of WorkQueues serviced by the threadpool. 
    */ 
    public int numberOfWorkQueues(); 

    /** 
    * This method will return the minimum number of threads maintained by the threadpool. 
    */ 
    public int minimumNumberOfThreads(); 

    /** 
    * This method will return the maximum number of threads in the threadpool at any 
    * point in time, for the life of the threadpool 
    */ 
    public int maximumNumberOfThreads(); 

    /** 
    * This method will return the time in milliseconds when idle threads in the threadpool are 
    * removed. 
    */ 
    public long idleTimeoutForThreads(); 

    /** 
    * This method will return the current number of threads in the threadpool. This method 
    * returns a value which is not synchronized. 
    */ 
    public int currentNumberOfThreads(); 

    /** 
    * This method will return the number of available threads in the threadpool which are 
     * waiting for work. This method returns a value which is not synchronized. 
    */ 
    public int numberOfAvailableThreads(); 

    /** 
    * This method will return the number of busy threads in the threadpool 
    * This method returns a value which is not synchronized. 
    */ 
    public int numberOfBusyThreads(); 

    /** 
    * This method returns the number of Work items processed by the threadpool 
    */ 
    public long currentProcessedCount(); 

     /**
     * This method returns the average elapsed time taken to complete a Work
     * item.
     */
    public long averageWorkCompletionTime();

    /** 
    * This method will return the name of the threadpool. 
    */ 
    public String getName(); 

}

// End of file.
